Entomopathogenic Nematodes for Field Control of Onion Maggot (Delia antiqua) and Compatibility with Seed Treatments.

Onion maggot (Delia antiqua) is a prominent pest of allium crops in temperate zones worldwide. Management of this pest relies on prophylactic insecticide applications at planting that target the first generation. Because effective options are limited, growers are interested in novel tactics such as deployment of entomopathogenic nematodes. We surveyed muck soils where onions are typically grown to determine if entomopathogenic nematode species were present, and then evaluated the compatibility of entomopathogenic nematode species with the insecticides commonly used to manage D. antiqua. We also evaluated the efficacy of these entomopathogenic nematodes for reducing D. antiqua infestations in the field. No endemic entomopathogenic nematodes were detected in surveys of muck fields in New York. Compatibility assays indicated that, although insecticides such as spinosad and, to some extent, cyromazine did cause mortality of entomopathogenic nematodes, these insecticides did not affect infectivity of the entomopathogenic nematodes. Field trials indicated that applications of entomopathogenic nematodes can reduce the percentage of onion plants killed by D. antiqua from 6% to 30%. Entomopathogenic nematodes reduced D. antiqua damage and increased end of season yield over two field seasons. Applications of entomopathogenic nematodes may be a viable option for reducing D. antiqua populations in conventional and organic systems. Together with other management tactics, like insecticide seed treatments, applications of entomopathogenic nematodes can provide a yield boost and a commercially acceptable level of D. antiqua control.

Comparative transcriptome and metabolome analyses identified the mode of sucrose degradation as a metabolic marker for early vegetative propagation in bulbs of Lycoris.

Vegetative propagation (VP) is an important practice for production in many horticultural plants. Sugar supply constitutes the basis of VP in bulb flowers, but the underlying molecular basis remains elusive. By performing a combined sequencing technologies coupled with ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry approach for metabolic analyses, we compared two Lycoris species with contrasting regeneration rates: high-regeneration Lycoris sprengeri and low-regeneration Lycoris aurea. A comprehensive multi-omics analyses identified both expected processes involving carbohydrate metabolism and transcription factor networks, as well as the metabolic characteristics for each developmental stage. A higher abundance of the differentially expressed genes including those encoding ethylene responsive factors was detected at bulblet initiation stage compared to the late stage of bulblet development. High hexose-to-sucrose ratio correlated to bulblet formation across all the species examined, indicating its role in the VP process in Lycoris bulb. Importantly, a clear difference between cell wall invertase (CWIN)-catalyzed sucrose unloading in high-regeneration species and the sucrose synthase-catalyzed pathway in low-regeneration species was observed at the bulblet initiation stage, which was supported by findings from carboxyfluorescein tracing and quantitative real-time PCR analyses. Collectively, the findings indicate a sugar-mediated model of the regulation of VP in which high CWIN expression or activity may promote bulblet initiation via enhancing apoplasmic unloading of sucrose or sugar signals, whereas the subsequent high ratio of hexose-to-sucrose likely supports cell division characterized in the next phase of bulblet formation.

Integration of Nitrogen and Biofertilizer on the Agronomic Efficiency and Quality of Shallot (Allium ascalonicum L.) Plant in the Rainy Season.

BACKGROUND AND OBJECTIVE: In the rainy season farmers don't interest to cultivate shallot because in addition to providing a high dosage of fertilizer they are also sensitive to pathogenic attacks so they are afraid of crop failure and cause low shallot production. This study aimed to knew effect of agronomic component and quality of shallot under different concentrations of biofertilizer and Ammonium Sulphate (AS) fertilizer dose in the rainy season. MATERIALS AND METHODS: The study was conducted in Cangkring, Srandakan, Bantul, Special Region of Yogyakarta Indonesia from August to October 2019. The study was arranged in RCBD factorial with three replications. The first factor was a various dose of ammonium sulphate (100, 200 and 300 kg ha-1). The second factor was various concentrations of biofertilizer (2, 3 and 4%), and control. The observed variables were the analysis of growth yield and quality component of shallot plant. The analyzed using analysis of variance at 5% of significance then continued by DMRT at 5% of significance. RESULTS: There was the interaction between the application of AS dosage and biofertilizer concentration on all of variable observations. There was a significant difference between treatment with control on all of the observation variables. CONCLUSION: The combination of AS fertilizer 200 kg ha-1 dose and 3% biofertilizer concentration increased agronomic efficiency, growth, bulbs yields, and quality of bulbs include provitamin A, oleoresin compounds.

Transcriptome-wide association study and eQTL analysis to assess the genetic basis of bulb-yield traits in garlic (Allium sativum).

BACKGROUND: Garlic bulbs are abnormal expanding axillary buds that are rarely found among vascular plants. Bulb-yield is one of the valuable agronomic traits of garlic. However, due to the large genome size and a strictly asexual life cycle in the cultivars, the genetic basis of the yield traits are poorly understood in garlic. RESULTS: In the present study, we carried out an association mapping for three yield traits of garlic bulbs: bulb weight (BW), diameter (BD), and the number of garlic cloves (CN), using the recently proposed transcriptome-referenced association study. In total 25, 2, and 30 single nucleotide polymorphisms (SNPs), were identified in the transcripts to be associated with BW, BD, and CN traits, respectively. Of the transcripts with associated SNPs, the expression of 17 of them showed a significant correlation with the corresponding traits in the population, suggesting their relation to bulbs yield traits. Six transcripts were long non-coding RNAs (lncRNAs), and the others encode proteins involved mainly in carbohydrate metabolism, transcription regulation, cytokinin activity, protein degradation, etc. In addition, expression quantitative trait locus (eQTL) and expression correlation analysis have revealed that seven CN-related transcripts displayed interrelation, constituting two potential pathways. CONCLUSION: This study provides novel insights into the genetic basis of the yield traits in garlic bulbs, and the identification of trait-associated SNPs/transcripts provides a basis for improving the bulb yield in garlic breeding.